Neural interface system with edge array

ABSTRACT

The neural interface system of one embodiment includes a cylindrical shaft, a lateral extension longitudinally coupled to at least a portion of the shaft and having a thickness less than a diameter of the shaft, and an electrode array arranged on the lateral extension and radially offset from the shaft, including electrode sites that electrically interface with their surroundings. The method of one embodiment for making the neural interface system includes forming a planar polymer substrate with at least one metallization layer, patterning on at least one metallization layer an electrode array on a first end of the substrate, patterning conductive traces on at least one metallization layer, rolling a portion of the substrate toward the first end of the substrate, and securing the rolled substrate into a shaft having the first end of the substrate laterally extending from the shaft and the electrode array radially offset from the shaft.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.13/416,775, filed on Mar. 9, 2012, now U.S. Pat. No. 9,008,747, whichclaims the benefit of U.S. Provisional Patent Application Ser. No.61/451,083, entitled “Neural interface system with edge array” and filed9 Mar. 2011, the entirety of which is incorporated herein by thisreference.

TECHNICAL FIELD

This invention relates generally to the neural interface field, and morespecifically to a new and useful neural interface system with an edgearray in the neural interface field.

BACKGROUND

Neural interface systems are typically implantable devices that areplaced into biological tissue (e.g., brain or other neural tissue) andhave the ability through electrode sites, to record electrical signalsfrom and/or electrically stimulate the tissue. Such neural interfacesystems may be used, for example, in treatment of neurological andpsychiatric disorders. For instance, deep brain stimulation devices mayprovide controllable electrical stimulation of selected regions ofneural tissue through strategic positioning and activation of electrodesites.

A neural interface system including a high-density array of electrodesites would he useful in many applications for exceptional control, bututilizing current conventional technology, including more electrodesites typically means a significant increase in thickness and overallsize of the implantable device. Generally speaking, the larger theimplantable device is, the more damage to tissue (e.g., cortical bloodvessels and local tissue in and around the region of interest) thedevices inflicts during implantation into the tissue. Furthermore,larger devices typically experience increased incidence of tissueencapsulation, as a result of foreign body response, thereby leading todecreased electrode sensitivity.

Thus, there is a need in the neural interface field to create a new anduseful neural interface system that ameliorates or eliminates the issuescreated by larger devices. High-channel count neural interfacesespecially tend to be larger given the cost of decreasing the featuresize during fabrication. This invention provides such a neural interfacesystem, which is described in detail below in its preferred embodimentswith reference to the appended drawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic of the system of a preferred embodiment;

FIG. 2 is a schematic of a cross-sectional view of the shaft of thesystem of a preferred embodiment;

FIG. 3 is a schematic of the shaft of the system of a preferredembodiment;

FIGS. 4A-4B are schematics of variations of the lateral extension of thesystem of a preferred embodiment;

FIGS. 5A-5C are schematics of variations of electrical subsystems of thesystem of a preferred embodiment;

FIGS. 6 and 7 are flowcharts depicting the method of a preferredembodiment and variations thereof;

FIG. 8A is a schematic view depicting the step of forming a planarpolymer substrate (S210) having an electrode array and conductive tracespatterned on a metallization layer for a neural interface system 200;

FIG. 8B is an enlarged view of the indicated area in FIG. 8A;

FIG. 9 is a schematic view illustrating coupling an insert to thesubstrate (5242) shown in FIGS. 8A and 8B and then rolling the substratearound the insert (S244);

FIG. 10A is a schematic view illustrating securing the rolled substrateshown in FIG. 9 into a shaft (S250);

FIG. 10B is an enlarged view of the indicated area in FIG. 10A; and

FIGS. 11A, 11B, 11C(i)-(iii), 11D and 11E are schematics comparingtissue damage imparted by an exemplary neural interface system of apreferred embodiment to tissue damage imparted by conventional planarand microwire neural devices.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of preferred embodiments of the invention isnot intended to limit the invention to these preferred embodiments, butrather to enable any person skilled in the art to make and use thisinvention.

Neural Interface System

As shown in FIGS. 1 and 2, in a preferred embodiment, the neuralinterface system 100 of a preferred embodiment includes: a substantiallycylindrical shaft 110; a lateral extension 140 longitudinally coupled toat least a portion of the shaft 110 along a longitudinal direction ofthe shaft 110 and having a thickness less than a diameter of the shaft110; and an electrode array 150, at least partially arranged on thelateral extension 140 and radially offset from the shaft 110, comprisinga plurality of electrode sites 152 that electrically interface withtheir surroundings. The neural interface system 100 of the preferredembodiment preferably provides ultra-high density, high-resolutionmicroelectrodes on a shaft 110 implantable in tissue for electricallycommunicating with and interfacing with tissue, such as for recordingand/or stimulation of targeted tissue. The neural interface system 100is preferably used to interact with brain tissue or other neural tissuefor research and/or clinical purposes, but additionally or alternativelycan be used to interact with any suitable tissue for any suitableapplication. The electrode array 150 is preferably radially offset fromand is smaller than the shaft 110, such that the degree of any tissuedamage incurred by implantation of the shaft 110 will preferably havereduced effect on the electrode recording and/or stimulation quality andlongevity. The neural interface system 100 preferably reduces localtissue damage, such as to cortical blood vessels and damage in thedendritic arbor of local neurons, such as during implantation. Theneural interface system 100 preferably further reduces the occurrence oftissue encapsulation (arid associated biofouling and impedance effects)around the device, which would otherwise degrade the capabilities of theneural interface system 100. Furthermore, in one preferred embodiment,the components of the neural interface system are modular, which mayhelp to reduce costs.

The shaft 110 of the preferred neural interface system 100 preferablyfunctions to provide structural support for the neural interface system.As shown in FIG. 2, the shaft 110 of the preferred system 100 can beconfigured as a rolled substrate 120. The substrate 120 is preferably asubstantially planar substrate 120 that is rolled into a cylindricalshaft 110. Alternatively, the shaft 110 can be any suitable shape formedby processes other than rolling; for example, the shaft 110 can befolded into a particular shape, or the shaft 110 can include a singletube or plurality of nested tubes. The shaft 110 preferably hassubstantially circular cross-section taken along a radial direction, butcan alternatively have an elliptical or any suitable cross-sectionalshape.

In the preferred system 100, the substrate 120 includes a polymer orother suitable material that is flexible enough to be rolled orsimilarly manipulated. The substrate 120 preferably includes one or moremetallization layers and/or one or more insulation layers interspersedbetween the metallization layers. As shown in FIG. 1, one or moremetallization layers are preferably patterned into conductive traces 126within the substrate 120. The metallization layers are preferablyfurther patterned into the electrode sites 152 of the electrode array150, as further described below. In a preferred embodiment, thesubstrate 120 includes at least one metallization layer, but thesubstrate can alternatively include any suitable number of metallizationlayers. The metallization layers preferably include platinum and/oriridium, but can additionally or alternatively include any suitableconductive or semi-conductive material. The insulation layers preferablyinclude silicon carbide, but may additionally or alternatively includeany suitable electrically insulating material such as silicon dioxide,silicon nitride, parylene, polyimide, LCP, and/or silicone. At leastsome of the layers of the substrate 120, such as the metallizationlayers, may be planarized by chemical-mechanical planarization oranother smoothing process. Any additional suitable photolithographicprocesses can be performed on the substrate as desired.

As shown in FIG. 1, the substrate 120 can further include a bond padregion 128 that electrically communicates with the conductive traces 126and/or electrode array 150, and with other circuitry and electronicdevices (e.g., controller and/or signal processing devices). The bondpad region 128 is preferably on a proximal portion of the substrate 120(with respect to the system when the system is implanted in tissue). Forexample, in a preferred embodiment, in an application in which theneural interface system is implanted in brain tissue, the bond padregion 128 is on or near a proximal end of the shaft 110, near oroutside the surface of the brain. However, the bond pad region 128 canalternatively be located in any suitable portion of the substrate, ormay be arranged in any suitable position relative to the shaft 110.

In a variation of the preferred system 100 shown in FIG. 3, the shaft110 defines a lumen 130 within its interior space. The lumen 130preferably passes longitudinally within the shaft 110. In somevariations of the preferred system 100, the lumen 130 is centered withinthe shaft 110, and in some variations, the lumen 130 is offset withinthe shaft 110. The lumen 130 can function to deliver and/or receivesubstances or items in different manners in one or more differentvariations. In another variation of the preferred system, the lumen 130is configured to receive and transport a fluid 132, such as for fluidicdelivery of drugs or other therapeutic molecules to tissue surroundingthe implanted shaft 110.

In another variation of the preferred system 100 shown in FIG. 3, thesystem 100 includes a stylet 134 that is insertable in the lumen 130 andpreferably functions to at least provide structural support for theshaft 110 during implantation. The stylet 134 preferably includes asharpened, pointed distal end to aid insertion into tissue and/oradjustment within tissue. In another variation of the preferred system100, the stylet 134 includes a microwire that is insertable in the lumen130 and preferably functions as a single channel microelectrode. Inanother variation of the preferred system 100, the stylet 134 functionsas a mandrel, around which the substrate 120 is wrapped to form theshaft 110, as further described below.

In another variation of the preferred system 100 shown in FIG. 3, thesystem 100 further includes an optical light source 136 that isinsertable in the lumen 130 and preferably functions to facilitateoptogenetic stimulation. In particular the optical light source 136facilitates optogenetic stimulation using optogenetic tools withlight-sensitive ion channels in tissue to perturb neural circuits withcell-type specificity. The optical light source 136 is preferably anoptical fiber, but may alternatively be any suitable light source. Inthis variation, the optical light source may operate within the neuralinterface system 100 similar to that described in U.S. PatentPublication No. 2011/0112591 entitled “Waveguide neural interfacedevice”, the entirety of which is incorporated herein by this reference.

Other variations of the preferred system 100 can include any othersuitable substance, material, insert, and/or machine insertable withinthe lumen 130. Preferably, the substance or insert disposed within thelumen 130 includes a bioresorbable material that is absorbed into thesurrounding tissue after a period of time. Furthermore, in someembodiments, the substance or insert disposed within the lumen 130 ispermanently coupled to the shaft 110. However, in some embodiments thesubstance or insert disposed within the lumen 130 is temporarily coupledto the shaft 110. For example, in one embodiment, the stylet 134 isdecoupled from the shaft 110 after the substrate 120 is wrapped into ashaft 110, or retracted and/or removed from the shaft 110 after theneural interface system 100 is implanted in tissue. In some embodiments,the system 100 includes multiple substances or inserts disposed withinthe lumen 130.

In another variation of the preferred system 100 shown in FIGS. 5B and5C, at least the first electrical subsystem 160 is disposed within thelumen 130 of the shaft 110. At least a portion of the conductive traces126 preferably extend radially inward toward the lumen 130 and arecoupled to the first electrical subsystem 160 within the lumen 130. Inanother variation of the preferred system 100, the conductive traces 126pass approximately circumferentially around the shaft 110 within thesubstrate 120, spiraling and approaching radially inward. The firstelectrical subsystem 160 (and/or any other electrical components) withinthe lumen 130 is preferably coupled to the second electrical subsystem180 or other suitable components positioned external to the shaft)through the lumen 130, such as on or within the substrate 120, through ahardwired connection 170 (FIG. 5B), or through a wireless connection(FIG. 5C). In an alternative embodiment, both the first and secondelectrical subsystems 160, 180 can be disposed within the lumen.

As shown in FIGS. 4A and 4B, the system 100 can also include a lateralextension 140. The lateral extension 140 preferably functions toradially or laterally offset the electrode array 150 from the shaft 110.The lateral extension 140 is preferably longitudinally coupled to atleast a portion of the shaft 110, such as along the entire length of theshaft 110, a distal portion of the shaft 110 (FIG. 4A), or any suitableportion of the shaft 110. As shown in FIG. 4A, the lateral extension 140is preferably coupled in a continuous manner with the shaft 110.Alternatively, as shown in FIG. 4B, the lateral extension 140 can becoupled to the shaft by a series of one or more ribs bridging thelateral extension and shaft, which thereby form a perforated framework142 between the shaft and lateral extension with openings 144.

As shown in the FIGURES, the lateral extension 140 is preferably atrailing end of the rolled substrate 120 of the shaft 110. In otherwords, the lateral extension 140 is preferably an unrolled portion ofthe substrate 120 left outside of the rolled portion of the substrate120. For example, as shown in FIGS. 1A and 1B, the lateral extension 140can project substantially tangentially from the shaft 110 in a rolldirection of the rolled substrate of the shaft 110. In anotheralternative embodiment, the lateral extension 140 can be originallyseparate from the shaft 110, and coupled to the shaft 110 to laterallyextend tangentially from the shaft 110, or extend in any suitabledirection.

The lateral extension 140 preferably has a thickness that is less thanthe diameter of the shaft 110. Preferably, the lateral extension 140 hasa subcellular thickness, such as approximately five μm thick, whichpreferably reduces damage to local tissue during implantation.Furthermore, reactive tissue cells are less likely to adhere to thelateral extension 140 of subcellular thickness as part of a typicalforeign body response of the tissue, such that the lateral extension 140and the electrode array 150 preferably experience a reduced amount oftissue encapsulation, which typically interferes with system operation.

As shown in the FIGURES, the preferred system 100 can also include anelectrode array 150. The electrode array 150 preferably functions toelectrically interface with surrounding tissue. In a preferredembodiment, the electrode array 150 is a high-density array withapproximately one hundred, and more preferably at least several hundred,microelectrode sites 152. Alternatively, the electrode array 150 caninclude any suitable number of electrode sites. As shown in FIGS. 1A and1B, the electrode array 150 is preferably at least partially arranged onthe lateral extension 140, more preferably along a longitudinal edge ofthe lateral extension 140, and is radially offset from the shaft 110.The electrode array 150 preferably includes recording electrode sitesand/or stimulation electrode sites that are formed in any suitablephotolithographic process on the lateral extension 140. Preferably, theelectrode sites 152 are formed by patterning and selectively exposingportions of the lateral extension 140 to reveal underlying metallizationlayers, and/or by building and patterning additional metallizationlayers on the lateral extension 140. However, the specific structure andformation, of the electrode sites 152 may depend on the particularapplication of the neural interface system.

As shown in FIGS. 5A-5C, the preferred neural interface system 100includes a first electrical subsystem 160 that functions to communicatesignals to and/or from the electrode array 150 and a second electricalsubsystem 180 that processes signals from the electrode array 150. Thefirst electrical subsystem 160 preferably includes an amplifier thatamplifies signals received from the electrode array 150 and transmitsamplified signals to the second electrical subsystem 180. The firstelectrical subsystem 160 preferably further includes a multiplexer thatmultiplexes neural signals to and/or from the electrode array 150,thereby enabling the neural interface system 100 to include fewerconductive traces than would otherwise be required. The secondelectrical subsystem 180 is preferably in communication with the firstelectrical subsystem 160, and preferably includes a signal processor,controller, and/or any suitable electronics.

As shown in FIG. 5A, in one preferred embodiment, the first electricalsubsystem 160 and/or second electrical subsystem 180 are coupled to aproximal region of the substrate 120 of the shaft 110. As shown, theconductive traces 126 preferably pass along the shaft generally in alongitudinal direction toward the bond pad region 128 or other proximalregion of the substrate 120. Electrical signals are preferablycommunicated between the conductive traces 126 and the first electricalsubsystem 160 and/or second electrical subsystem 180 through the bondpad region 128 and a hardwire connector 170 (e.g., a ribbon cable).However, the signals can additionally or alternatively be communicatedwith a wireless transmitter.

In another variation of the preferred system 100 shown in FIGS. 5B and5C, at least the first electrical subsystem 160 is disposed within thelumen 130 of the shaft no. At least a portion of the conductive traces126 preferably extend radially inward toward the lumen 130 and arecoupled to the first electrical subsystem 160 within the lumen 130. Inanother variation of the preferred system 100, the conductive traces 126pass approximately circumferentially around the shaft no within thesubstrate 120, spiraling and approaching radially inward. The firstelectrical subsystem 160 (and/or any other electrical components) withinthe lumen 130 is preferably coupled to the second electrical subsystem180 or other suitable components positioned external to the shaft)through the lumen 130, such as on or within the substrate 120, through ahardwired connection 170 (FIG. 5B), or through a wireless connection(FIG. 5C). In an alternative embodiment, both the first and secondelectrical subsystems 160, 180 can be disposed within the lumen.

Although omitted for clarity, the preferred embodiments of the system100 include every combination of the variations of the shaft 110,lateral extension 140, electrode array 150, electrical subsystems 160,180, and other components described herein. The preferred embodiments ofthe system 100 also include every combination of the stylet 134 or otherinserts into the lumen 130 of the shaft 110, including none, one, or aplurality of such inserts into the lumen 130 of the shaft 110 asdescribed above.

Method of Making a Neural Interface System

As shown in FIG. 6, a preferred method of making a neural interfacesystem 200 includes: forming a planar polymer substrate in block S210;patterning a plurality of conductive traces in block S220, patterning anelectrode array on a first end of the substrate in block S230, rolling aportion of the substrate towards the first end of the substrate in blockS240, and in block S250, securing the rolled substrate into a shaft. Theshaft preferably has the first end of the substrate laterally extendingfrom the shaft and the electrode array radially offset from the shaft.

As shown in FIG. 6, block S210 recites forming a planar polymersubstrate. Forming a planar polymer substrate preferably functions toprepare a structure from which the shaft, lateral extension, conductivetraces, and/or electrode array is formed. In a preferred embodiment,block S210 includes depositing a plurality of metallization layers anddepositing a plurality of insulation layers interspersed between themetallization layers. However, any suitable number of metallizationlayers and/or insulation layers can be deposited. Any suitabledeposition technique or process (e.g., chemical vapor deposition) can beused. The metallization layers can be any suitable conductive material,such as platinum or iridium or gold, including appropriate metaladhesion layers. In a preferred embodiment, the insulation layers aresilicon carbide, but may alternatively be any suitable insulatingmaterial. In some embodiments, the metallization layers and insulationlayers are of near equal thickness, but in other embodiments at leastsome of the metallization layers and/or insulation layers may be ofdifferent thicknesses. As shown in FIG. 7, one variation of thepreferred method can include depositing at least one metallization layerin block S211, planarizing at least one metallization layer in blockS212, depositing at least one insulation layer in block S213, and/orplanarizing at least one insulation layer in block S214. Planarizingpreferably involves chemical-mechanical planarization, but the preferredmethod may additionally or alternatively include any suitable smoothingprocess. As shown in FIG. 6, block S220 recites patterning an electrodearray on a first end of the substrate, and block S230 recites patterninga plurality of conductive traces.

As shown in FIGS. 8A and 8B, the electrode array and conductive tracesare preferably patterned on one or more metallization layers of thesubstrate. Blocks S220 and S230 preferably function to form a pluralityof electrode sites configured to interface with tissue, and a pluralityof conductive traces configured to carry signals to and from theelectrode sites. Blocks S220 and S230 can include any suitablephotolithographic processes (e.g., masking, patterning, etching).Another variation of the preferred the method further includes forming abond pad region on the substrate that is configured to communicate withelectrical subsystems and the conductive traces and/or electrode array.

As shown in FIG. 6, the method preferably includes block S232, whichrecites depositing an insulation layer onto the conductive traces andelectrode array. Similar to block S210, the insulation layer can includesilicon carbide, but may alternatively include suitable insulatingmaterial, and can be deposited in any suitable manner. Furthermore, anysuitable number of insulation layers can be deposited.

As shown in FIG. 6, block S240 recites rolling a portion of thesubstrate toward the first end of the substrate. Block S240 preferablyfunctions to form a shaft of the neural interface device. As shown inFIG. 9, in a preferred embodiment, the method includes block S242, whichrecites coupling an insert to a second end of the substrate. Thepreferred method can further include block S244, which recites rollingthe portion of the substrate around the insert from the second endtoward the first end. The insert is preferably an elongated insert, andmore preferably includes a stylet such as a microwire, an optical fiber,or any suitable insert configured to serve as a mandrel around which theshaft is formed. The insert is preferably coupled to the unrolledsubstrate by any suitable fastening mechanism, such as tacking with abiocompatible epoxy or another adhesive. In a preferred embodiment, themethod includes coupling the insert to a rotational actuator and rollingthe portion of the substrate around the insert with the rotationalactuator. The rotational actuator is preferably a stepper motor, but maybe a servomotor, crank, or any suitable actuator. The actuator ispreferably programmed to roll a predetermined portion of the substrate(e.g., to include up to a predetermined length of the substrate in therolled shaft), thereby leaving a portion of the substrate outside of therolled shaft. In this embodiment, a first end of the insert ispreferably coupled (e.g., with a shaft coupler) to the rotationalactuator and a second end of the insert opposite the first end may bemounted to a fixture to help stabilize the insert as the substrate isrolled. After the substrate is rolled, the insert is preferablydecoupled from the actuator such that the shaft of the neural interfacedevice is independent and separate from the actuator.

As shown in FIGS. 6 and 10A-10B, block S250 recites securing the rolledsubstrate into a shaft. The shaft preferably has a lateral extensionwith the electrode array radially offset from the shaft. In a firstvariation, securing the rolled substrate includes applying abiocompatible epoxy or other adhesive between at least two rolled layersof the shaft. In a second variation, securing the rolled substrateincludes applying a biocompatible epoxy or other adhesive on a proximaland/or distal end face of the shaft.

The preferred method can further include forming a sharpened distal endon the shaft in block S260. Block S260 functions to configure the shaftfor insertion into tissue and/or adjustment within tissue. In apreferred variation, as shown in FIG. 8B, block S260 includes formingthe substrate with at least one slanted edge. In this variation, theslanted edge is formed into sharpened edge or point when the substrateis rolled. In an alternative variation, block S260 includes machining asharpened edge or point onto the substrate after the shaft is rolled.The preferred method can further include reinforcing the distal end ofthe shaft to better bear load, such as with a hardening treatment (e.g.,chemical, treatment) of the substrate material, forming the substrate tohave a thicker and/or stronger material at a distal end, and/or couplinga reinforcing material to the distal end of the substrate and/or shaft.

Although omitted for clarity, the preferred embodiments of the methodincludes every combination and permutation of the processes describedherein. It should be understood that any of the foregoing processesand/or blocks can be performed by any suitable device, in any suitableorder, in a serial or parallel manner.

Example Implementation of the Preferred System and Method

The following example implementation of the preferred system and methodis for illustrative purposes only, and should not be construed asdefinitive or limiting of the scope of the claimed invention. In oneexample, the shaft includes a polymer substrate having threemetallization layers that are approximately 0.7 μm, 1.0 μm, and 1.3 μmthick. The metallization layers are interspersed with silicon carbideinsulation layers. A trailing end of the substrate is patterned withphotolithographic processes to form a high-density electrode arrayincluding approximately 670 microelectrode sites. When the substrate isunrolled, at least a portion of the planar substrate has a width ofapproximately 450 μm and a thickness of approximately 5 μm. A microwirehaving a diameter of approximately 80 μm is tacked onto an end of theplanar substrate opposite the trailing end, and the planar substrate isrolled or wrapped around the microwire, toward the trailing end, to forma shaft approximately 10 mm long and having a lateral extensionprojecting tangentially from the shaft. The high-density electrode arrayis arranged along the edge of the lateral extension such that theelectrode array is radially offset from the rolled shaft.

The neural interface system is preferably strategically implanted tominimize damage to a target region of interest in the tissue, especiallycompared to conventional planar and microwire neural devices. As shownin FIGS. 11A and 11B, a planar neural device can sever portions of aneuron during implantation, and/or can be forced to record and/orstimulate tissue further from a desired target region in order to avoidexcessive damage to the target region. As shown in the schematics ofFIGS. 11C(i)-(iii), an exemplary planar neural device with a width ofapproximately 100 μm (FIG. 11C(i)) and an exemplary microwire neuraldevice with a diameter of approximately 30 μm (FIG. 11C(ii)) areestimated to result in a larger area of damage (A_(d)) to a desiredtarget region due to their larger footprint area or “effective width” inthe target region, compared to the neural interface system with an edgearray with an effective width of 5 μm (FIG. 11C(iii)). The shaft of theneural interface system is preferably positioned relatively distant fromthe target region, while the edge electrode array on the lateralextension (which is preferably thinner than the shaft and consequentlycauses less damage to the surrounding tissue than the shaft) ispreferably positioned in the target region of tissue with less damage tothe target region. In other words, in this simulated comparison, theneural interface system with an edge array preferably has asubstantially smaller effective width, and results in a substantiallysmaller area of damage (A_(d)) than the exemplary planar array neuraldevice (FIGS. 11D and 11E) or the exemplary microwire neural device(FIG. 11E).

As a person skilled in the art will recognize from the previous detaileddescription and from the figures and claims, modifications and changescan be made to the preferred embodiments of the invention withoutdeparting from the scope of this invention defined in the followingclaims.

What is claimed is:
 1. A method of making a neural interface system,comprising: a) forming a planar polymer substrate with at least onemetallization layer; b) patterning, on at least one metallization layer,an electrode array on a first end of the substrate; c) patterning aplurality of conductive traces on at least one metallization layer; d)rolling a portion of the substrate toward the first end of thesubstrate; and e) securing the rolled substrate into a shaft having thefirst end of the substrate laterally extending from the shaft and theelectrode array radially offset from the shaft.
 2. The method of claim1, wherein forming the planar polymer substrate includes planarizing theat least one metallization layer.
 3. The method of claim 1, whereinrolling a portion of the substrate into the shaft comprises coupling aninsert to a second end of the substrate and rolling the portion of thesubstrate around the insert from the second end to the first end.
 4. Themethod of claim 3, wherein rolling a portion of the substrate into theshaft further comprises coupling the insert to a rotational actuator androlling the portion of the substrate around the insert with therotational actuator.
 5. A method for providing a neural interfacesystem, comprising the steps of: a) providing a substrate by: i) forminga substantially cylindrical shaft as a rolled portion of the substrate;and ii) providing a lateral extension portion of the substrate, thelateral extension extending longitudinally from at least a portion ofthe shaft and having a thickness less than a diameter of the shaft; andb) supporting at least a portion of an electrode array on the lateralextension, the portion of the electrode array supported on the lateralextension being radially offset from the shaft, c) wherein the electrodearray comprises a plurality of electrode sites that are configured toelectrically interface with their surroundings.
 6. The method of claim5, including providing the lateral extension as a trailing end of therolled substrate.
 7. The method of claim 5, including providing thelateral extension being tangent to the shaft.
 8. The method of claim 5,including providing the rolled substrate defining a lumen.
 9. The methodof claim 8, including configuring the lumen to receive and transport afluid.
 10. The method of claim 9, including disposing an optical lightsource within the lumen.
 11. The method of claim 5, including providingthe substrate having conductive traces coupled to the electrode array.12. The method of claim 11, including providing the conductive tracesextending from the electrode array to a bond pad region of thesubstrate.
 13. The method of claim 8, including providing an amplifierat least partially disposed within the lumen.
 14. The method of claim11, including providing a multiplexer at least partially disposed withinthe lumen.
 15. The method of claim 5, including providing the substratehaving conductive traces electrically coupling from the electrode arrayto a first electrical subsystem, and configuring the first electricalsubsystem to wirelessly communicate with a second electrical subsystem.16. The method of claim 5, including providing the lateral extensionhaving a slanted distal edge extending to a sharpened distal end of theshaft.
 17. The method of claim 5, including providing the electrodearray arranged at least partially along a longitudinal edge of thelateral extension.
 18. The method of claim 5, including providing theelectrode array comprising at least one of a recording electrode siteand a stimulation electrode site.
 19. The method of claim 5, includingproviding the substrate as a polymer substrate.
 20. The method of claim5, including providing the substrate as a polymer substrate having threemetallization layers interspersed with silicon carbide insulationlayers.
 21. The method of claim 20, including providing themetallization layers being from about 0.7 μm to 1.3 μm thick.
 22. Themethod of claim 5, including providing at least one rib bridging fromthe lateral extension to the shaft.
 23. The method of claim 22,including providing the lateral extension being coupled to the shaft byat least two bridging ribs, thereby forming a perforated frameworkbetween the shaft and lateral extension with at least one openingbounded by the ribs.